Radar systems have traditionally been used to detect relatively large objects up to hundreds of miles away from a high power transmitting radar antenna. Contemporary systems are commonly used to detect relatively dense objects or object surfaces that are multiple square feet in surface profile, such as potential collision surfaces relative to a vehicle (e.g., road surfaces, walls, vehicle panels, and/or other potential collision surfaces). While traditional radar systems have used (and still commonly use) rotating or actuated antennas in order to scan the radar over a large solid angle or to track objects/surfaces, more contemporary systems can employ arrays of antennas in order to scan solid angles without requiring physical motion of the array and/or to provide a more directional high gain transmit or receive beam than typically possible with a single antenna element.
However, contemporary radar systems are still generally too bulky, inefficient, and insensitive to be able to detect the position of objects and/or surfaces on the scale of a human finger reliably, or to differentiate between the positions and profiles of multiple fingers on a single human hand, a stylus and a human finger, and/or other common user interface mechanisms, or to be implemented in a form compact and efficient enough to be wearable or implemented as a user interface for a portable user device, such as a smart phone. Thus, there is a need in the art for systems and methods to provide efficient, reliable, and accurate sensing of positions of objects, particularly in the context of radar systems employing an array of antennas.
In addition, unmanned aerial vehicles (UAVs), sometimes referred to colloquially as drones, are a popular technology that can be used for various commercial applications including traffic monitoring, news reporting, fire monitoring for firefighting, survey of construction sites, package delivery, land surveillance, and others. In most contemporary applications, the UAV needs to have robust communication with its controller, mostly to provide visual information of the UAV's environment back to its controller. The UAV controller also needs to communicate commands to the UAV. Typically, the communications are facilitated by a bidirectional wireless link between the UAV and its controller that solely supports communication of information or data. Conventional consumer UAVs would benefit from radar-like capabilities, but conventional radar systems are typically heavy, require high data bandwidths, and/or are power hungry, and so conventional UAV systems, particularly consumer UAVs, operate without radar. Thus, there is a need in the art for systems and methods to provide efficient, reliable, and accurate sensing of positions of UAVs, particularly in the context of communication systems employing an array of antennas.
Embodiments of the present disclosure and their advantages are best understood by referring to the detailed description that follows. It should be appreciated that like reference numerals are used to identify like elements illustrated in one or more of the figures.